Windrowers are equipped with one of several types of detachable headers having a cutter assembly (e.g., rotary or sickle-type) and one or more pairs of hydraulically-driven, oppositely rotating, conditioner rolls that are used to condition (e.g., crush, macerate) harvested crop material and deposit the conditioned crop material onto the ground as a swath or windrow. The conditioning process serves to facilitate drying of the crop material. The extent of conditioning is based in part on the tensioning of the conditioner rolls as administered using a hydraulic circuit. In general, the tensioning of the conditioner rolls is typically achieved at the header through manual adjustment of a shut-off valve and a switch to enable hydraulic fluid flow and subsequent control through activation of control valves of the hydraulic circuit. The control valves are electrically coupled to the switch and hydraulically coupled to hydraulic cylinders. The hydraulic cylinders are in turn coupled via a respective pivot assembly to opposing ends of at least one of the respective pairs of rolls to cause, upon the control of hydraulic fluid flow to and from the hydraulic cylinders by switching-activation of the control valves, an adjustment in resistance to movement of at least one roll of the pair relative to the other roll. In effect, the control of hydraulic fluid flow via operator manipulation of the shut-off valve, activation of the control valves via the switch, and shut-off valve manipulation permits the charging of pressure of an accumulator tank from a pumping source in the hydraulic circuit and the reduction in charge pressure of the accumulator (and release of flow into a reservoir). A pressure gauge coupled to the hydraulic circuit guides the operator in his or her adjustments.